Chemical Engineering Commons^™

Tio2 Assisted Photodegradation For Low Substrate Concentrations And Transition Metal Electron Scavengers, Hassan A. Alsaud, Ahmed E. Abibat, Roger Painter, Lonnie Sharpe, Samuel Keith Hargrove

Mechanical and Manufacturing Engineering Faculty Research

Some contaminants of emerging concern (CECs) are known to survive conventional wastewater treatment, which introduces them back to the environment, allowing them to potentially cycle into drinking water. This is especially concerning because of the inherent ability of some CECs to induce physiological effects in humans at very low doses. Advanced oxidation processes (AOPs) such as TiO2-based photocatalysis are of great interest for addressing CECs in aqueous environments. Natural water resources often contain dissolved metal cation concentrations in excess of targeted CEC concentrations. These cations may significantly adversely impact the degradation of CECs by scavenging TiO2 surface generated electrons. Consequently, …

Rates Of Cavity Filling By Liquids, Dongjin Seo, Alex M. Schrader, Szu-Ying Chen, Yair Kaufman, Thomas R. Cristiani, Steven H. Page, Peter H. Koenig, Yonas Gizaw, Dong Woog Lee, Jacob N. Israelachvili

Faculty Publications

Understanding the fundamental wetting behavior of liquids on surfaces with pores or cavities provides insights into the wetting phenomena associated with rough or patterned surfaces, such as skin and fabrics, as well as the development of everyday products such as ointments and paints, and industrial applications such as enhanced oil recovery and pitting during chemical mechanical polishing. We have studied, both experimentally and theoretically, the dynamics of the transitions from the unfilled/partially filled (Cassie–Baxter) wetting state to the fully filled (Wenzel) wetting state on intrinsically hydrophilic surfaces (intrinsic water contact angle < 90°, where the Wenzel state is always the thermodynamically favorable state, while a temporary metastable Cassie–Baxter state can also exist) to determine the variables that control the rates of such transitions. We prepared silicon wafers with cylindrical cavities of different geometries and immersed them in bulk water. With bright-field and confocal fluorescence microscopy, we observed the details of, and the rates associated with, water penetration into the cavities from the bulk. We find that unconnected, reentrant cavities (i.e., cavities that open up below the surface) have the slowest cavity-filling rates, while connected or non-reentrant cavities undergo very rapid transitions. Using these unconnected, reentrant cavities, we identified the variables that affect cavity-filling rates: (i) the intrinsic contact angle, (ii) …

Catalysts For Nitrogen Reduction To Ammonia, Royce D. Duda, Julie N. Renner

Faculty Scholarship

The production of synthetic ammonia remains dependent on the energy- and capital-intensive Haber-Bosch process. Extensive research in molecular catalysis has demonstrated ammonia production from dinitrogen, albeit at low production rates. Mechanistic understanding of dinitrogen reduction to ammonia continues to be delineated through study of molecular catalyst structure, as well as through understanding the naturally occurring nitrogenase enzyme. The transition to Haber-Bosch alternatives through robust, heterogeneous catalyst surfaces remains an unsolved research challenge. Catalysts for electrochemical reduction of dinitrogen to ammonia are a specific focus of research, due to the potential to compete with the Haber-Bosch process and reduce associated carbon …

Modeling Soot Formation From Solid Complex Fuels, Alexander J. Josephson, Rod R. Linn, David O. Lignell

Faculty Publications

A detailed model is proposed for predicting soot formation from complex solid fuels. The proposed model resolves two particle size distributions, one for soot precursors and another for soot particles. The precursor size distribution is represented with a sectional approach while the soot particle-size distribution is represented with the method of moments and an interpolative closure method is used to resolve fractional methods. Based on established mechanisms, this model includes submodels for precursor coagulation, growth, and consumption, as well as soot nucleation, surface growth, agglomeration, and consumption. The model is validated with comparisons to experimental data for two …

Photocatalytic Carbon Dioxide Conversion To Fuel For Earth And Mars, Anne J. Meier

USF Tampa Graduate Theses and Dissertations

As far as we know, we only have one planet to live on, with a delicate atmospheric system providing us safety and life. Global CO2 emissions continue to plague the environment of Earth, primarily due to the processing of fossil fuels, deforestation, and industrialization. There are several avenues of pursuing CO2 reutilization, each having their own benefits and limitations. Direct and indirect thermochemical approaches of CO2 conversion boast of efficient CO2 conversion rates but have limitations associated with the use of renewable hydrogen and high temperatures of operation. The work in this dissertation investigates low temperature photocatalytic CO2 conversion, a …

Texas Sour Orange Juice Used In Scaffolds For Tissue Engineering, Mandana Akia, Nataly Salinas, Cristobal Rodriguez, Robert Gilkerson, Luis A. Materon, Karen Lozano

Mechanical Engineering Faculty Publications

Fine fibers of polyhydroxybutyrate (PHB), a biopolymer, were developed via a centrifugal spinning technique. The developed fibers have an average diameter of 1.8 µm. Texas sour orange juice (SOJ) was applied as a natural antibacterial agent and infiltrated within the fibrous membranes. The antibacterial activity against common Gram-positive and Gram-negative bacteria (Staphylococcus aureus and Escherichia coli, respectively) was evaluated as well as cell adhesion and viability. The PHB/SOJ scaffolds showed antibacterial activity of up to 152% and 71% against S. aureus and E. coli, respectively. The cell studies revealed a suitable environment for cell growth and cell attachment. The outcome …

Pressure Swing Adsorption Separation Of H2s/Co2/Ch4 Gas Mixtures With Molecular Sieves 4a, 5a, And 13x, Howell H. Heck, Merilyn L. Hall, Rudy Dos Santos, Manolis M. Tomadakis

Mechanical and Civil Engineering Faculty Publications

Pressure swing adsorption experiments were carried out for the separation of equimolar mixtures of carbon dioxide and methane containing small amounts of hydrogen sulfide, utilizing 4A, 5A, and 13X molecular sieves. High-purity methane of zero or nearly zero hydrogen sulfide concentration was produced in the adsorption stage with 13X and 5A sieves, at high product recovery rates; high-purity carbon dioxide was obtained with the same sieves in the desorption stage. Zeolite 4A was found capable of raising considerably the hydrogen sulfide concentration in the accumulated desorption product (vs. the adsorption feed) at high recovery rates too. Adsorption selectivity values derived …

Methods And Systems For Identifying A Particle Using Dielectrophoresis, Adrienne Minerick, Jeana Collins, Kaela M. Leonard, Tayloria N.G. Adams

Michigan Tech Patents

A system for identifying a particle. The system includes a microfluidic device; a microelectrode array including a plurality of electrodes, the microelectrode array disposed within the microfluidic device; a plurality of particles suspended in a solution and delivered to the microelectrode array using the microfluidic device; a signal generator operatively coupled to the microelectrode array; a particle detector adjacent to the microelectrode array; and a controller in operative communication with the signal generator and the particle detector. The controller is configured to apply an oscillating voltage signal to the microelectrode array between a low frequency and a high frequency at …

Hydrogels For Cell Delivery, Esmaiel Jabbari

Faculty Publications

No abstract provided.

Properties Of Matter, Mike Jackson, Holly Haney

High School Lesson Plans

Students will investigate the relationship(s) between thermal and electrical properties of matter. First, students will use a multimeter and temperature probe to investigate the relationship between electrical resistance and temperature of an electrical resistor composed of metals. They will then graph collected data to analyze the relationship and draw a conclusion as to their relationship. They will then perform the same investigation on a thermal resistor made of a semiconducting substance and analyze that collected data. Finally, using ClaimEvidence-Reasoning (CER) structure, students will use their experimental evidence to state the similarities and differences between the electro-thermal properties of metals and …

What Can I Do As A Student To Make A Positive Impact On The Environment?, Tammy Guthrie, Greg Herzig, Kathy Prophet, Cassie Kautzer

Middle School Lesson Plans

Students discover ways they can make a positive impact on the environment.

Gekko Optimization Suite, Logan Beal, Daniel Hill, Ronald Abraham Martin, John Hedengren

Faculty Publications

This paper introduces GEKKO as an optimization suite for Python. GEKKO specializes in dynamic optimization problems for mixed-integer, nonlinear, and differential algebraic equations (DAE) problems. By blending the approaches of typical algebraic modeling languages (AML) and optimal control packages, GEKKO greatly facilitates the development and application of tools such as nonlinear model predicative control (NMPC), real-time optimization (RTO), moving horizon estimation (MHE), and dynamic simulation. GEKKO is an object-oriented Python library that offers model construction, analysis tools, and visualization of simulation and optimization. In a single package, GEKKO provides model reduction, an object-oriented library for data reconciliation/model predictive control, and …

Homogeneous Reaction Kinetics Of Carbohydrates With Viologen Catalysts For Biofuel Cell Applications, Hilary Bingham

Theses and Dissertations

Energy usage is continually on the rise and significant efforts are being extended to provide more renewable energy. One area of exploration is the development of fuel cells, which includes biofuel cells that can extract energy from carbohydrates obtained from biomass. Recently, viologen catalysts have been shown to enhance reaction rates of energy extraction and improve carbohydrate conversion efficiencies. However, characterizing the effects of process parameters such as pH, reactant concentrations, and carbohydrate exposure time to buffer solutions with a rigorous model is lacking. This thesis characterizes the homogeneous reaction between carbohydrates and a methyl viologen catalyst to provide insights …

Smart Technologies For Oil Production With Rod Pumping, Brigham Wheeler Hansen

Theses and Dissertations

This work enables accelerated fluid recovery in oil and gas reservoirs by automatically controlling fluid height and bottomhole pressure in wells. Several literature studies show significant increase in recovered oil by determining a target bottomhole pressure but rarely consider how to control to that value. This work enables those benefits by maintaining bottomhole pressure or fluid height. Moving Horizon Estimation (MHE) determines uncertain well parameters using only common surface measurements. A Model Predictive Controller (MPC) adjusts the stroking speed of a sucker rod pump to maintain fluid height. Pump boundary conditions are simulated with Mathematical Programs with Complementarity Constraints (MPCCs) …

Microwave-Assisted Synthesis Of Palladium Nanoparticles Supported On Copper Oxide In Aqueous Medium As An Efficient Catalyst For Suzuki Cross-Coupling Reaction, Hany A. Elazab, M. A. Sadek, Tamer T. El-Idreesy

Chemical and Biochemical Engineering Faculty Research & Creative Works

We report here a reliable green method for the synthesis of palladium nanoparticles supported on copper oxide as a highly active and efficient catalyst for Suzuki cross-coupling reaction. The experimental synthetic approach is based on microwave-assisted chemical reduction of an aqueous mixture of palladium and copper salt simultaneously using hydrazine hydrate as reducing agent. The catalyst was fully characterized using various techniques showing well-dispersed palladium nanoparticles. The catalytic activity and recyclability of the prepared catalyst were experimentally explored in the ligand-free Suzuki cross-coupling reaction with a diverse series of functionalized substrates. The synthesized Pd/CuO catalyst shows many advantages beside its …

Significant Improvement In Tio₂ Photocatalytic Activity Through Controllable Zro₂ Deposition, Xiaofeng Wang, Rajankumar L. Patel, Xinhua Liang

Chemical and Biochemical Engineering Faculty Research & Creative Works

ZrO₂ was deposited on anatase TiO₂ nanoparticles using 5-80 cycles of atomic layer deposition (ALD). The photocatalytic activity of all samples was evaluated based on the degradation of methylene blue (MB) solution under UV light. The TiO₂ sample with 45 cycles of ZrO₂ deposition (45c-Zr/TiO₂, 1.1 wt% ZrO₂) was proved to be the most efficient catalyst with a degradation kinetic constant 10 times larger than that of the pure TiO₂ sample. All samples were characterized using inductively coupled plasma atomic emission spectroscopy (ICP-AES), nitrogen adsorption-desorption, X-ray diffraction (XRD), transmission electron microscopy …

Arrhenius Rate Chemistry-Informed Inter-Phase Source Terms (Arciist), Matthew J. Schwaab, Robert B. Greendyke, Bryan J. Steward

Faculty Publications

Currently, in macro-scale hydrocodes designed to simulate explosive material undergoing shock-induced ignition, the state of the art is to use one of numerous reaction burn rate models. These burn models are designed to estimate the bulk chemical reaction rate. Unfortunately, these burn rate models are largely based on empirical data and must be recalibrated for every new material being simulated. We propose that the use of Arrhenius Rate Chemistry-Informed Interphase Source Terms (ARCIIST) in place of empirically derived burn models will improve the accuracy for these computational codes. A reacting chemistry model of this form was developed for the cyclic …

Integrated Scheduling And Control In Discrete-Time With Dynamic Parameters And Constraints, Logan Beal, Damon Petersen, David R. Grimsman, Sean Warnick, John Hedengren

Faculty Publications

Integrated scheduling and control (SC) seeks to unify the objectives of the various layers of optimization in manufacturing. This work investigates combining scheduling and control using a nonlinear discrete-time formulation, utilizing the full nonlinear process model throughout the entire horizon. This discrete-time form lends itself to optimization with time-dependent constraints and costs. An approach to combined SC is presented, along with sample pseudo-binary variable functions to ease the computational burden of this approach. An initialization strategy using feedback linearization, nonlinear model predictive control, and continuous-time scheduling optimization is presented. The formulation is applied with a generic continuous stirred tank reactor …

Comparative Study Of Different Sensor Array Designs Involving Plasticized Polymer Coatings For Btex Detection In Water, Nicholas Post

Master's Theses (2009 -)

Detection and quantification of benzene, toluene, ethylbenzene, and xylenes (BTEX) in liquid phase is of interest because of the significant public health hazards posed by these compounds. BTEX are volatile organic compounds (VOCs) commonly used as additives in gasoline. Shear horizontal surface acoustic wave (SH-SAW) devices have shown promise in liquid phase sensing applications and is used to address this problem. SH-SAW devices can be made chemically sensitive by depositing a polymer coating on the device surface. SH-SAW devices coated with commercially available polymers have shown modest sensitivity to BTEX compounds. However, there are few polymers which exhibit the properties …

Software For Peak Finding And Elemental Composition Assignment For Glycosaminoglycan Tandem Mass Spectra, John D. Hogan, Joshua A. Klein, Jiandong Wu, Pradeep Chopra, Geert Jan Boons, Luis Carvalho, Cheng Lin, Joseph Zaia

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glycosaminoglycans (GAGs) Covalently Linked to Proteoglycans (PGs) Are Characterized by Repeating Disaccharide Units and Variable Sulfation Patterns Along the Chain. GAG Length and Sulfation Patterns Impact Disease Etiology, Cellular Signaling, and Structural Support for Cells. We and Others Have Demonstrated the Usefulness of Tandem Mass Spectrometry (MS 2 ) for Assigning the Structures of GAG Saccharides; However, Manual Interpretation of Tandem Mass Spectra is Time-Consuming, So Computational Methods Must Be Employed. in the Proteomics Domain, the Identification of Monoisotopic Peaks and Charge States Relies on Algorithms that Use Averagine, or the Average Building Block of the Compound Class Being Analyzed. …

Aerothermodynamic Analysis Of A Mars Sample Return Earth-Entry Vehicle, Daniel A. Boyd

Mechanical & Aerospace Engineering Theses & Dissertations

Because of the severe quarantine constraints that must be imposed on any returned extraterrestrial samples, the Mars sample return Earth-entry vehicle must remain intact through sample recovery. Vehicles returning on a Mars-Earth trajectory will attain velocities exceeding any that have been experienced by prior space exploration missions, with velocities approaching 14 km/s. Velocities as high as these will encounter significant heating during atmospheric re-entry to Earth.

The purpose of this study has been to systematically investigate the aerothermodynamic challenges that will result from a Mars sample return, Earth-entry vehicle design. The goal was to enable efficient estimation of maximum stagnation …

Isru Thermal-Driven Processes On Interplanetary Surfaces And Characteristics On Production Of Commodities, Jesus A. Dominguez

Theses and Dissertations

Extraterrestrial In-Situ Resource Utilization (ISRU) is a primary area of interest to enable successful exploration, mining, and human settling in space missions. Native extraterrestrial conditions, such as vacuum conditions and low gravity are challenging as their effects on workable-scale ISRU operations are basically unknown. This dissertation research work studied three thermal-driven properties on JSC-lA lunar regolith simulant at pilot-plant-­scale under vacuum (a native ambient condition on the moon and asteroids): (1) gasification and decomposition of regolith's components that have the potential of generating gaseous oxygen, metals, and alloys without the necessity of terrestrial precursors, (2) vacuum void formation during the …

Synthesis Of Double Network Hydrogels Which Can Be Shaped Freely, Natsuki Morimoto, Norie Kato

The International Student Science Fair 2018

Double network (DN) hydrogels have specific characters such as flexibility and high mechanical strength. They are expected to use biomaterials such as artificial cartilages and meniscuses. The purpose of this study is to synthesize DN gels which can be shaped freely. DN gels were synthesized by polyvinyl alcohol (PVA) as a mold, 2-acrylamide-2-methylpropane sulfonic acid (AMPS) as a first monomer, N,N’-methylene-bis-acrylamide (MBAA) as a crosslinker, 2-oxoglutalic acid (OGA) as an initiator and acrylamide (AAm) as a second monomer. First, PVA (polymerization degree; 2000) was dissolved in the water and prepared to 15 % of aqueous solution. It was poured in …

An Entirely New Molecular Glue For Mof Using Unusual Structural Transformation Of A Coordination Polymer, Sukwoo Jung, Hangyeol Kim, Junseok Ahn

The International Student Science Fair 2018

In this research, an entirely new molecular glue is reported. This ‘coordination polymer glue’ is synthesized from zinc metal and BDC-NPE(2,5-bis{4-[1-(4-nitrophenyl)ethylamino]butoxy}terephthalic acid). Molecular glue transforms from 1D coordination polymer to a 3D cross-linked framework, resulting in a phase change of solution to solid. The carboxylate group of this glue makes the preformed MOF bind to its framework. Therefore, when the solution of molecular glue is mixed with preformed MOF powder and heated, homogeneous and thin MOF film – MOF/ZnNPE film – is fabricated. The film is irrelevant to the kind of its substrate, and its thermal stability was enhanced in …

The Fate Of Nitrogen And Faecal Coliform In The Lubigi Wetland In Uganda, Aloyce Mayo

Tanzania Journal of Engineering and Technology (TJET)

The capacity of the Lubigi wetland to reduce nitrogen and faecal coliform pollution entering Lake Kyoga in Uganda was investigated. Three transects with 5 sampling points in each, were established in the wetland. Wetland plants samples were collected from the specific locations along the transects, and laboratory tests and analyses were carried out for plants biomass and nitrogen contents determination. Samples of wetland sediments were also collected, and laboratory tests and analyses were done for determination of nitrogen content in the sediments. Wetland water samples were taken from the main wetland inlet and the main outlet from the wetland main …

Effects Of Methyl-Blue Addition In Sewage Substrate On The Performance Of Microbial Fuel Cell, Joseph H. Kihedu Dr.

Tanzania Journal of Engineering and Technology (TJET)

Experimental study was undertaken to evaluate performance of microbial fuel cell. Without addition of methyl blue, the cell generated 1.265 V, 0.403 mA and 56.12 mW/m2 after three hours of operation. With 300 µM methyl blue in sewage anolyte, 6.7% increase in voltage, 20.5% increase in current and 28.6% increase in power density was observed. By using ash water catholyte, addition of methyl blue in anolyte led to increase of 9.0% in voltage, 38.5% in current and 50.9% for power density. Between three and twenty four hours of continuous operation of the cell with phosphate buffer catholyte, the average voltage …

Defect Laden Metal Oxides And Oxynitrides For Sustainable Low Temperature Carbon Dioxide Conversion To Fuel Feedstocks, Debtanu Maiti

USF Tampa Graduate Theses and Dissertations

The current energy and environmental scenario in the world demands acute attention on sustainable repurposing of waste CO2 to high value hydrocarbons that not only addresses the CO2 mitigation problem, but also provides pathways for a closed loop synthetic carbon cycle. Difference in the scales of global CO2 emissions (about 40 Gtpa, 2017) and the carbon capture and sequestration (CCS) facilities (estimated cumulative 40 Mtpa, 2018) provokes active research on this topic. Solar thermochemical (STC) and visible light photocatalysis are two of the most promising routes that have garnered attention for this purpose. While STC has the advantages of high …

Chemical Stability Investigations Of Catalyst Layer In Pemfc, Yan-Yan Gao, Ming Hou, Yong-Yi Jiang, Dong Liang, Jun Ai, Li-Min Zheng

Journal of Electrochemistry

This work was intended to study the effect of free radicals on the chemical stability of catalyst layer via ex situ accelerated stress test (AST). Fenton reagent was used as the free radical provider in this research. Apart from the decomposition of Nafion in catalyst layer, the agglomerated Pt nanoparticles and the corroded carbon support were also observed after being treated in Fenton reagent for 100 h. Firstly, the existence of fluoride (F) ions evidenced the chemical decomposation of Nafion after being attacked by trace radical species, which was supported by the intensity decrease in the C-F stretching and vibration …

Recent Progress For Fe-N-C Electrocatalysts In Alkaline Fuel Cells, Xin Deng, Heng-Quan Chen, Ye Hu, Qing-Gang He

Journal of Electrochemistry

Fuel cells are highly recommended nowadays due to their intrinsic advantages such as high energy conversion efficiency, nearly no pollution, and convenient operation. With the development of anion exchange membrane, alkaline fuel cells have gone through a renaissance thanks to their superiorities such as faster reaction kinetics, wider choices for both fuels and electrocatalysts. It is essential to find an appropriate electrocatalyst for oxygen reduction reaction (ORR) to improve the performance of alkaline fuel cells. Further commercialization of the widely used Pt-based materials has suffered from disadvantages such as scarcity and high cost. As alternatives to largely investigated Pt-based materials, …

Pt/G-C3N4 Nanosheet For Visible Light-Induced Enhancement Of The Activity For Formic Acid Electro-Oxidation, Yong-Rong Sun, Chun-Yu Du, Guo-Kang Han, Ya-Jing Wang, Yun-Zhi Gao, Ge-Ping Yin

Journal of Electrochemistry

By using graphitic carbon nitride nanosheet (g-C₃N₄ nanosheet) as a support,Pt/g-C₃N₄ nanosheet catalyst was fabricated by microwave assisted polylol process. The nanoparticles size,composition,structure and optical properties of Pt/g-C₃N₄ nanosheet were characterized by TEM,XRD,XPS and UV-Vis diffuse reflectance spectroscopy. Comparing with the catalytic activities toward formic acid electro-oxidation under dark and visible light illumination,the superior activity of Pt/g-C₃N₄ nanosheet catalyst was achieved under visible light illumination. This visible light-driven enhancement in the formic acid performance could be attributed to the plasmon-induced electron-hole separation on g-C₃N₄ with …